Funds are requested to purchase a VisualSonics Vevo 2100 research ultrasound imaging system for the Cardiovascular Phenotype Core at the University of Iowa. The Core was founded in 2002 with NIH funds. In the time since, the Core has provided about 20,000 imaging studies in mice and rats, and has introduced a number of novel methods for assessment of organ structure and function in vivo. In 2010, a Vevo 2100 system was purchased with NIH funds. Usage of that instrument has exceeded projections by > 50%; reaching 3113 studies in 2013. Recruitment of new NIH-funded faculty, whose research depends on animals housed in a pathogen-free barrier facility, will increase demands on the existing Vevo 2100 system beyond its capacity. Accommodation of new Users, along with existing Users, will incur significant hardship, expense, and compromise of experimental design unless an additional Vevo 2100 system is purchased. This request coincides with the launch of a new paradigm-shifting initiative by the University of Iowa Carver College of Medicine (UICCOM). The requested instrument will be housed and operated in the new Pappajohn Biomedical Discovery Building, which will open in June, 2014, at a cost of $147M. Two whole floors of that building will be devoted to research imaging, managed by the Iowa Institute for Biomedical Imaging (IIBI). Commensurate with this new vision, IIBI will provide state of the art space and infrastructure for the requested instrument without financial encumbrance. UICCOM will fund the instrument's service contract. The Cardiovascular Research Center will provide funds for faculty and technical personnel to operate the instrument. Together, the institution will provide $213,350 per year for operation of the requested instrument alone, in addition to space and infrastructure. The requested instrument will support the research of NIH-funded investigators in the fields of hypertension, vascular disease, cardiac arrhythmia, cardiomyopathy, and valvular heart disease. The Core will build on its track record of innovation and productivity, and on its history of training new imaging scientists.